This invention relates to the threshing, separating and cleaning of harvested grain. It relates more specifically to a harvesting apparatus.
It is envisaged that the invention will find application in the field of threshing of grain like maize (corn), wheat, beans, and the like, more particularly in the field of harvesting grain having lightweight or small, or both lightweight and small grain kernels such as wheat.
For purposes of this specification, the term xe2x80x9cthreshingxe2x80x9d (and derivatives thereof) should be interpreted as including threshing, separating and cleaning (and corresponding derivatives thereof).
Combine harvesters use rotary threshing and separation units to harvest grain like maize, wheat, beans and the like (hereinafter xe2x80x9cgrainxe2x80x9d). To thresh grain, it is required to separate the grain from the ears, pods and the like. After separating the grain from the ears, pods and the like, grain must be separated from the chaff, broken straw, debris and the like (hereinafter xe2x80x9cchaffxe2x80x9d). A fan or blower is used for this purpose whereby the fan produces an air flow stream that carries off or separates chaff from the grain. The chaff is carried off or separated from the grain because the chaff is lighter in weight than the grain. It is apparent that the air flow stream is crucial in the process of separating the grain from the chaff.
Grain harvesting threshing and separation units work satisfactory in dry conditions and when harvesting maize. Under these conditions, the fan or blower is able to provide sufficient suction to move air through the rotor housing itself and through the sieve openings into the space between the sieve and the grain collecting element to move grain kernels. However, in humid conditions or when harvesting different grains like wheat, barley, rice or other crops, clogging may occur in the rotor housing or in the space between the sieve and the grain collecting element. Grain loss increases in such conditions, and the cleaning grade of the grain might deteriorate. This occurs because the suction from the fan or blower at the end of the rotor housing is inadequate under these conditions. Unfortunately because the suction is inadequate, the sieve openings clog and grain kernels cannot pass. This limits the performance and throughput of the combine grain harvesting threshing and separation unit""s cleaning device.
The present invention is directed to overcoming one or more of the problems set forth above.
An aspect of the invention is to improve the performance of the rotary threshing and separation unit in extreme conditions.
In another aspect of the invention there is provided a device to improve performance of the rotary threshing and separation unit by creating an air flow stream in at least the separation zone between the sieve and grain collector element thereby preventing the openings in the sieve from getting clogged with chaff.
In another aspect of the invention there is provided at least one opening to allow an air flow stream between the sieve and grain collection element to improve the functioning of the rotary threshing and separation unit
In another aspect of the invention there is provided openings in the sieve to achieve a sufficient air flow stream into the rotor housing.
In another aspect of the invention there are openings arranged to allow an air flow stream to flow in a cross or counter flow direction with respect to the feeding direction of the grain between the sieve and the grain collecting element thereby improving the separation of chaff from the grain by moving or carrying away the chaff because of its lighter weight with respect to the grain kernels.
In still another aspect of the invention there are flaps wherein air flow streams may pass to facilitate the separation of chaff and grain kernels and wherein the opening widths of said flaps are manually or automatically adjusted depending on the desired air flow stream speed and intensity that may be dependent upon the crop to be harvested, throughput desired and the other working conditions.
In still another aspect of the invention there are grain loss sensor senses located at the discharge end of the rotor housing that transmits signals to an electronic controller that computes a setting value for the drives of said flaps, and wherein the drives control the widths of the openings of the flaps thereby allowing for an automatic adjustment.
In still another aspect of the invention there is a fan or blower having a rotational speed and throughput capacity that is adjustable or variable to vary of control the speed of the air flow stream wherein said adjustment is dependent upon the crop to be harvested, desired throughput and other harvesting conditions.
In another aspect of the invention there is provided a second fan or blower for generating an auxiliary air flow stream between the sieve and the grain collector element.
In another aspect of the invention there are openings arranged to allow an air flow stream in a cross or counter flow to the feeding direction of the grain moving between the sieve and grain collecting element.
In yet another aspect of the invention there is an inexpensive and simple embodiment having one fan or blower to produce both a main air flow stream and auxiliary air flow stream.
The advantages described above and hereinafter for the improved designs described in the subclaims for the first embodiment also apply for the improvements described in the subclaims for the second embodiment. Further, preferred embodiments of the invention are described in further subclaims. The above aspects are merely illustrative and should not be construed as all-inclusive.